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Space Science

Survey Finds No Hint of Dark Matter Near Solar System 125

Posted by Soulskill
from the did-you-check-under-the-couch-cushions dept.
Eponymous Hero writes "Does dark matter exist or doesn't it? It seems these results don't shed as much light as we'd hoped. 'Moni Bidin says he's not sure whether dark matter exists or not. But he says that his team's survey (PDF) is the most comprehensive of its type ever done, and the puzzling results must be reckoned with. "We don't have a good comprehension of what is going on," he says.' This has the smell of a Neutrinogate scandal, but at least we've been warned about the shoulder shrugging. 'As an example, Newberg notes that the researchers assumed that the group of stars they examined were smoothly distributed above and below the plane of the Milky Way. But if the distribution turns out to be lumpier, as is the case for stars in the outer parts of the galaxy, then the resulting calculations of dark matter density could be incorrect. Flynn agrees that there are a number of ways that the method employed by Moni Bidin and his co-authors "could get it wrong."'"
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Survey Finds No Hint of Dark Matter Near Solar System

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  • We have so much evidence about the existence of the dark matter that's not even funny: https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence [wikipedia.org]
    • by perles (1855088)
      Yes, it exists. We sitting on one piece of dark matter!
      • The Earth is not dark matter. Even discounting the wide array of man made radiation that our species puts out, the Earth also puts out a considerable amount of detectable radiation. It's just an insignificant amount in comparison to the sun.
    • by wisnoskij (1206448) on Friday April 20, 2012 @03:45PM (#39750313) Homepage

      We have seen its effect on the solar system but I don't think we have any really evidence for what exactly Dark Matter is?
      Is it matter? is it particles?
      We have theories on what Dark Matter is, but those theories could be completely wrong.

      So dark matter, as we know it, might not exist, all we know is that something is causing the effects that we see.

      • by buchner.johannes (1139593) on Friday April 20, 2012 @04:09PM (#39750613) Homepage Journal

        Dark matter is the name of the problem, not the solution.

        It may not be particles, but the universe is very well described by the cold dark matter particle model (plus dark energy).

        • Re: (Score:1, Flamebait)

          by jhoegl (638955)
          So dark matter is a filler. Much like religion.
          Great! So, if I dont know about something and I dont believe in religious things, Ill call it Dark Matter.
          Random person "What is behind the sun?"
          Me "I dunno... dark matter?"
          • Dark matter is the name of the problem, not the solution.

            It may not be particles, but the universe is very well described by the cold dark matter particle model (plus dark energy).

            So dark matter is a filler. Much like religion.

            Dark matter is the mismatch between observation and prediction in e.g. galaxy rotation curves. It looks as if there is additional matter there that doesn't radiate. "As if" is the key word here. What it actually is, is not explained by that name.

            If you had x$ at the start of the month, and now you have x/3$, and you know where x/3$ went, but not the last third, you can call that "unknown expenses". Same thing.

          • by geekoid (135745) <`moc.oohay' `ta' `dnaltropnidad'> on Friday April 20, 2012 @04:57PM (#39751115) Homepage Journal

            No.
            There is an effect. This is known, Dark Matter is the name for that effect until it is solved.
            The name is a place holder, not the effect. We measure and predict the effect. Something is impacting large bodies. We don't know what.

            It's like hears a loud banging on your wall, You know something is there, you just don't know what until you figure out a way to look.

            Religion has names for things that they can't show evidence for.

        • by Raenex (947668)

          Dark matter is the name of the problem, not the solution.

          No, it's a hypothesized solution to various problems seen in astronomy. You might have figured that out from the name itself.

          http://en.wikipedia.org/wiki/Dark_matter [wikipedia.org]

          "In astronomy and cosmology, dark matter is a currently unknown type of matter hypothesized to account for a large part of the total mass in the universe. Dark matter neither emits nor absorbs light or other electromagnetic radiation, and so cannot be directly seen with telescopes.[1] Dark matter is estimated to constitute 83% of the matter in t

    • by Anonymous Coward

      But, but, but There is a consensus!

      These people are just "Deniers".

    • by rainmouse (1784278) on Friday April 20, 2012 @03:52PM (#39750421)

      We have so much evidence about the existence of the dark matter that's not even funny: https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence [wikipedia.org]

      All indirect evidence. Personally the idea of an invisible, intangible, ethereal magical material that helps peoples sums add up is dubious at best. There are plenty of other good theories out there that do not include this populistic hypothesis.
      such as http://www.springerlink.com/content/g332701735121773/ [springerlink.com]

      • by hazem (472289) on Friday April 20, 2012 @04:13PM (#39750655) Journal

        that helps peoples sums add up is dubious at best.

        I think it's a bit more than just coming up with stuff willy nilly.

        We have these theories that work great for a lot of observations. They break down a bit for some observations, but can be "fixed" by adding dark matter. This either means the theories are wrong somehow, or there is something out there that's not been accurately observed, or maybe both. The key is to come up with experiments that can falsify the proposition that there is dark matter and that it's the cause of the aberrations.

        A nice analogy is the discovery of Neptune. The theories predicted the planets would move in such a way. However they didn't quite do that. But by assuming another planet (which had not been observed), they could get their sums to add up. The testable part of it was when they said, "look here, and you should find a planet that's causing these deviations", and behold, they did.

        The thing is, the current theories, even if they're wrong with dark matter, they're "close" to whatever the real situation is because they work so well in most cases. That means the "correct' theory won't be too extremely different, or must at least reduce to the current theories for the special cases we have observed.

        If there are competing but "good" theories out there, the key is to find out what differentiates them in their predictions, then to devise experiments to observe what happens in those cases. If you can't devise and carry out such experiments, then it's all mere speculation.

        • by HiThere (15173)

          The thing is, the current theories, even if they're wrong with dark matter, they're "close" to whatever the real situation is because they work so well in most cases. That means the "correct' theory won't be too extremely different, or must at least reduce to the current theories for the special cases we have observed.

          Well... that depends on what you mean by "too extremely different". If you accept that phlogiston was pretty close to the correct theory of combustion, then you are right. The predictions of the phlogiston theory were fairly close the the predictions of the current theory. But the mechanism was quite different. And in this case, also, the mechanism may well be quite different. Or maybe is *is* some undiscovered particle. But don't get fixated on that answer.

        • by Hentes (2461350)

          The thing is, the current theories, even if they're wrong with dark matter, they're "close" to whatever the real situation is because they work so well in most cases. That means the "correct' theory won't be too extremely different, or must at least reduce to the current theories for the special cases we have observed.

          They work in small scale, but most cases is streching it. Gravitational anomalies are pretty widespread, not just one or two special galaxies. Also, those 'theories' are without any predictive power, as they are mostly fit to existing data. In fact, "dark matter" itself is treated like a free variable in most of these theories, changing mass and distribution a hundred times to fit the observations. For the orbital speed of stars to be independent of their position in the galaxy, the distribution of dark mat

      • I like to think I have an open mind when it comes to cosmology, but I've never liked the Dark Matter "theory". If they ever find direct evidence, fine, but I will remain unconvinced until then.

        My personal favourite alternative hypothesis is called Modified Newtonian Dynamics, which is based on the idea that gravity exerts a stronger pull between objects that are more or less in the same inertial frame (ie at very low relative accelerations, that "acceleration is not linearly proportional to force at small v

        • by HiThere (15173)

          IIRC, MOND ran into some problems that it hasn't yet been able to solve. Doesn't mean some modified version won't work, of course.

          FWIW, Dark Matter + Dark Energy seem to me to cry out for a different answer. But I'm not a cosmologist, so I don't feel obliged to come up with a new theory consistent with all extant evidence.

        • by geekoid (135745)

          I would think the fact that the effect is not from a central point, but form many point is space substantially hinder the MOND theory, as well as the lensing issue.

          NO one 'invoked nonluminal matter.

        • by Bengie (1121981)
          They think this ghost matter exists because there are large sections of seemingly empty space with gravitational lensing but no detectable matter in any frequency.

          When "something" exerts HUGE amounts of gravity while being 100% transparent, we give it a generic name that that indicates that we don't understand it... "Dark Matter"
        • by damburger (981828)

          People who actually study this sort of thing don't find MOND to be "blasphemy" they find it to be "stupid".

          The thing is, you've dismissed the dark matter theory (no, it doesn't need scare quotes) clearly without understanding it. You seem to be laboring under the delusion that rotation curves are the only evidence for this matter. They are not. Most aspects of large scale cosmology invoke dark matter in some way - and what is more, they do so in ways that cannot be predicted by your favorite hypothesis.

          I su

      • by ankhank (756164) *

        > Personally the idea of an invisible, intangible, ethereal magical material
        > that helps peoples sums add up is dubious at best.

        Yeah, prayer never helped me with math.

      • by Anonymous Coward


        Personally the idea of an invisible, intangible, ethereal magical material that helps peoples sums add up is dubious at best.

        That's pretty much exactly how neutrinos were first theorized to exist by Pauli back in the 20s. It wasn't until the 50s that we actually observed them experimentally. The point being, we've found exactly what you're describing by looking for things that "help peoples sums add up" before.

      • by geekoid (135745)

        " Personally the idea of an invisible, intangible, ethereal magical material"

        Like gravity? or solar wind?

        Did you read the letter you linked to? You dio realize that he admits his proposal doesn't explain some effects we see? right?

        There is an effect. We can make predictions about the effect.

        SO something is happening. Proposed changes to the gravitation theory to explain the phenomena haven't played out.

        Could it be some weird aspect of large scale gravity? lensing?

        Sure, but the data for those ideas hasn't pl

      • All indirect evidence.

        Most of what we know comes from indirect evidence.

        Personally the idea of an invisible, intangible, ethereal magical material that helps peoples sums add up is dubious at best.

        For some reason the universe doesn't care what you're personally dubious about.

      • by ceoyoyo (59147)

        The problem with all the other theories is that they don't fit the data, all the data, as well as the cold WIMP dark matter hypothesis.

        Personally I find postulating weird vacuum interactions more of a stretch than unknown particles with properties very similar to known particles (neutrinos) that we already suspected existed for other reasons. But to each his own.

      • by damburger (981828)

        There is more to it than that, and to be frank the 'alternative' theories are not good. To call the accepted theories 'populist' is, by the way, a red flag that you can kind of a crank.

        This is a "hmm" results at best. What you have to understand is that this measurement is pretty local. They are very far from getting the big picture on this one despite being oversold in a press release.

        Also, why rushing to break the consensus on dark matter might not be the best idea: http://edgepenguin.com/content/darkmatt [edgepenguin.com]

    • by Anonymous Coward

      Hey guys! By definition, black holes have large mass and don't show themselves. We can only count the ones that are actively pulling in gas that gets heated up, or the ones we see with gravitational lensing. There could be zillions that we are unable to observe, along with dead stars, proto-solar-systems, low density dust clouds, etc. Dark energy is the real mystery.

      • by Charliemopps (1157495) on Friday April 20, 2012 @05:05PM (#39751191)
        Sorry, you're off base. Dark matter, whatever it is, has mass but does not interact with other matter or energy. This doesn't just mean that it doesn't give off or reflect light and radiation. It also means that it's transparent to light and radiation. Per observation, there are huge swaths of "dark matter" between us and other stars/galaxies. Yet we can see these radiation emitting bodies undistorted, so whatever is there generating the gravitational effect must be totally transparent to every form of radiation we can measure. "dark matter" was a poor choice in a name. It's not dark, and it very likely is not even matter.
        • by ceoyoyo (59147)

          Actually, you're both wrong. The dark matter most likely isn't normal matter because that doesn't agree with models of nucleosynthesis in the big bang. It probably is matter, because that hypothesis is the only one we've come up with that fits all the data reasonably well and doesn't require really weird new physics.

          Dark matter is weakly interacting, but it probably does interact with normal matter, just like neutrinos do. It doesn't emit light (because it doesn't interact with the electromagnetic force), e

        • so I guess we can't expect to shed much light on the matter? :-)

      • by HiThere (15173) <`charleshixsn' `at' `earthlink.net'> on Friday April 20, 2012 @05:21PM (#39751363)

        There's this problem that we think we know the number of baryons that existed in the first few nano-seconds, because of the cosmic abundance of Helium and Lithium. Black holes aren't particular about not swallowing baryons (in fact, they rather prefer to), so this causes problems. If Dark Matter is matter, it must be non-baryonic matter, or we need to redo LOTS of calculations...which is going to mean a major theoretical shift, and nobody has come up with a reasonable theory to shift to. It's much easier if it's not matter at all, but some other effect. (Maybe gravity interacts with gravitational fields at long distances?) Otherwise Dark Matter needs to be non-baryonic matter, and then you've still got Dark Energy to explain.

        • by lgw (121541)

          Note that this is cosmologist-speak, and so "non-baryonic matter" in much the same way that everything but hydrogen and helium is a "metal". If not for neutron decay, simple neutrons would fit the observational evidence from dark matter faily well. Dark matter may very well be similar enough to known (uncharged) baryons under the covers that it's just a matter of convention - yes, we might then need to redo many calculations, but that's an area so inelegant that almost no one is satisfied with the Standar

    • We have so much evidence about the existence of the dark matter that's not even funny

      And now there's evidence that there's not any in our immediate vicinity (article I read mentioned 13000 ly).

      Which means we need to come up with a reason why things work one way "way over there", and another way "right around here"....

      • Which means we need to come up with a reason why things work one way "way over there", and another way "right around here"....

        Would the existence of Kardashev Type 2 or 3 civilizations "way over there" present a valid hypothesis, or should I put the foil hat back on?

        • Which means we need to come up with a reason why things work one way "way over there", and another way "right around here"....

          Would the existence of Kardashev Type 2 or 3 civilizations "way over there" present a valid hypothesis, or should I put the foil hat back on?

          At this point, invoking Type2+ civilizations as the cause of the observations is effectively the same as invoking God - neither is testable, neither allows us to make predictions.

        • I've always wondered why no sci-fi writers (that I know of) have used this as a plot device. "There are millions of aliens that cloak themselves from us, since we're not mature enough yet" seems to be a kick-ass sci-fi explanation of dark matter.
    • No, it does not exist. All of these effects that are attributed to dark matter are all actually due to the fact that gravity does not actually travel at the speed of light. In fact, gravity slows down as it travels. This is why there appears to be more gravity at the edges of galaxies, and even at the edges of galaxy clusters. I also explains why we have such expansive gaps between galaxy clusters.
      • by Hatta (162192)

        Awesome. Where's your paper?

      • by geekoid (135745)

        fact huh? care to cite? no? jeez, who would have thought. You're an ignorant egomaniac to self deluded to know when he is out of knowledge and into wild ass making shit up.

    • It's depressing... (Score:5, Insightful)

      by StevenMaurer (115071) on Friday April 20, 2012 @05:21PM (#39751361) Homepage
      ...to see so many ignorant posts following up yours, clearly having not even read the article, being modded up - while your reference is stuck at a "1". Just to correct rainmouse's claim of mere "indirect" evidence, here is a quote from the link you provided:

      The most direct observational evidence to date for dark matter is in a system known as the Bullet Cluster. In most regions of the universe, dark matter and visible material are found together,[33] as expected because of their mutual gravitational attraction. In the Bullet Cluster, a collision between two galaxy clusters appears to have caused a separation of dark matter and baryonic matter. X-ray observations show that much of the baryonic matter (in the form of 107–108 Kelvin[34] gas, or plasma) in the system is concentrated in the center of the system. Electromagnetic interactions between passing gas particles caused them to slow down and settle near the point of impact. However, weak gravitational lensing observations of the same system show that much of the mass resides outside of the central region of baryonic gas.

      In other words, gravitational lensing of light waves - which is 100% direct evidence of matter - shows a region where there is matter that is clearly non-baryonic (i.e. does not interact with the electromagnetic field, a.k.a. "dark"). This is not subject to dispute. The question of what, exactly, is dark matter - is indeed still a subject of scientific research. There are, however, a number of super-symmetric theories which posit super-partners for well known particles, the most stable of which turn out to have the exact characteristics we're noting observationally. It is important to note that these theories were not tailored to account for the dark matter, but seem to fit the observational evidence quite well so far. As with all science however, theories are subject to falsification at any times as soon as new evidence comes on the scene.

  • by Anonymous Coward
    Here come the electric universe looneys
  • I'm not surprised (Score:4, Interesting)

    by hort_wort (1401963) on Friday April 20, 2012 @03:43PM (#39750271)

    I've never liked the theory of dark matter/energy. It always seemed to be a fudge factor thrown in to make the current theories work with what is observed. Astronomers have had good luck with that in the past, identifying planets and black holes based on gravitic effects, but they might have to a whole new approach to describe larger scales like this.

    I truly hope it isn't dark matter. I *want* there to be a new theory. We'd end up learning so much more from it!

    • Re:I'm not surprised (Score:4, Informative)

      by thegreatemu (1457577) on Friday April 20, 2012 @03:53PM (#39750429)

      At first, maybe. Dark matter was proposed to explain the high velocity of stellar orbits, and dark energy to explain the redshift of distant stars. However, cosmologists later used dark matter and dark energy theory to predict the angular spectrum of the cosmic microwave background and the baryon acoustic oscillation peak in galaxy distributions.

      Predictive power ftw!

      • by lgw (121541)

        Dark matter yes, dark energy no. The CMBR data gave quite accurate measurements that confirmed the dark matter explanation for galaxy rotation rates, and not the other explanations. Dark energy had nothing to do with it, and it's just a more fashionable name for the same old "cosmological constant".

        The CMBR data did suggest that the uniserve was at a more consistent temperature than it's age would suggest, but the "inflation" explanations of this were not existing theories, there was no pre-existing theor

    • by Kjella (173770)

      Somehow I don't see the problem with either solution:

      a) Dark matter is real. Then we have a whole new class of matter to investigate.
      b) Dark matter is not real. Then we have a new understanding of the forces around us.

      So what if it's real? The existence of dark matter particles would be a discovery about the size of finding the Higgs boson. It'd be way outside the Standard Model as we know it. We just need something more tangible on what exactly it is...

    • by FrootLoops (1817694) on Friday April 20, 2012 @04:53PM (#39751065)

      I understand that saying "we don't know what dark matter is" is unsatisfying, but some particles don't interact much with other particles. Neutrinos are a great example, since they only take part in the weak force and gravity (so not the electromagnetic or strong forces). Is it so hard to believe that some matter interacts solely through the gravitational force? That would mean no electromagnetic effects and almost no interactions with other forms of matter. Such matter would only be noticeable at gravity-dominated, cosmological scales.

      Who knows? Maybe there's a whole segment of matter humans are unfamiliar with which interacts very little with the matter we know about but interacts with itself in complicated ways. Maybe there are dark matter solar systems populated by dark matter people who are just as confused as we are about the weird gravitational anomalies caused by our otherwise invisible existence. Communicating through gravity would certainly be an interesting challenge! I don't really believe this, but my point is basically the same as Hamlet's: "There are more things in heaven and earth than are dreamt of in your philosophy"--that is, it's arrogant to expect humans to be in a position to observe all the parts of the universe. Perhaps some things are just hidden.

      • I didn't mean to imply that it wasn't possible because we couldn't see it. I was thinking about all the fudge factors from Newtonian mechanics that cleaned up once relativity was worked into it. Assuming that the fundamental rules we have are complete would also be arrogant, no? Rewriting equations for how spacetime works would be much, much more satisfying to me than identifying a new particle. I want warp drive.

        Also, totally different topic, my online personas are usually associated with Toucan Sam, s

        • Warp drive would be awesome. I'm not sure if a new particle (perhaps a new branch of particle physics?) or heavy revision to general relativity would be more satisfying to me as an explanation of dark matter / its purported effects. I'm not really knowledgeable enough in these matters to have a solid opinion either way. I just wanted to mollify what I see as a knee-jerk reaction against exotic dark matter and towards another Einstein-esque revision of previous notions about space and time

          About my name, I th

    • by s.petry (762400)

      I have been saying this for a long time. It's not logical that 80-90% of the Universe would be made up of something we have never seen or detected yet. The theory of course gives better credence to the current theories of Gravity and cosmology theories, but even when plugged in there is no consistent results.

      Heavy matter, not a problem. We know from observation that most of an atoms size is empty space. I can see how in massive gravity situations, that space would compress making more dense atoms. But

    • by jd (1658)

      It's also not a universally-applied fudge factor - globular clusters show no evidence of dark matter around their edges, regardless of how you perform the analysis.

      There's some good science indicating dark matter, but there's just as much that conflicts with it. Even if dark matter does turn out to exist, the fact that there's any conflict at all means that current dark matter theories are not merely a little too simple but have some facts plain wrong within the bounds for which they are defined.

    • by damburger (981828)

      "Interesting" for the same old knuckle-headed response that any resident of mount stupid [smbc-comics.com] gives whenever the phrase "dark matter" is mentioned? Clearly the mods are fellow mountaineers.

      Dark matter is not a 'fudge factor' to make the sums work. Dark matter is an interesting component of the universe we are only just learning about. Anyone who sits there and thinks that dark matter only exists to make rotation curves work clearly understands nothing about astrophysics.

      • "Interesting" for the same old knuckle-headed response that any resident of mount stupid [smbc-comics.com] gives whenever the phrase "dark matter" is mentioned?

        The knuckle-headed response is to wish for a more complete theory of the fundamental rules of the universe that would be the greatest thing to affect astrophysics since relativity? Dang. I'm terribly curious what the intelligent response would be! Please enlighten us, good sir!

        • by damburger (981828)

          You can wish all you like, but the Universe is not under any obligation to give you a neat solution.

          The intelligent response is to be skeptical of anyone who comes out with some flashy bit of research claiming to have overturned the consensus. The moment you claim an entire field of natural science is suppressing some obvious insight, you are a conspiracy theorist.

          • by Troed (102527)

            The intelligent response is to be skeptical of anyone who comes out with some flashy bit of research claiming to have overturned the consensus. The moment you claim an entire field of natural science is suppressing some obvious insight, you are a conspiracy theorist.

            A scientist should always be skeptical, sure. That includes being skeptical of "consensus".

            http://randi.org/site/index.php/swift-blog/1506-skeptic-history-a-tale-of-two-scientists.html [randi.org]

            • by damburger (981828)
              Being skeptical of the consensus doesn't mean throwing it away on one unconfirmed measurement.
              • by Troed (102527)

                It only takes one successful challenge to refute a hypothesis. It takes a new generation of scientists to grow up before the consensus is gone, since us humans sometimes have a hard time changing our convictions (and scientists are no different).

                "the hypothesis was generally met with skepticism from largely conservative scientists, who were resistant to any change in the status quo."

                http://deskarati.com/2012/01/06/alfred-wegeners-continental-drift-hypothesis/ [deskarati.com]

                • by damburger (981828)
                  This isn't a successful challenge. It isn't really a challenge at all. We are going to have to start thinking differently about how dark matter arranges itself in a galaxy, but the idea we are going to throw out dark matter is a fantasy coming straight from mount stupid.
  • by Anonymous Coward

    This summary is horrible. Not only do I not see anything in it about the headline (dark matter near the Solar System), but then it goes on about 'neutrinogate' (really?) without even mentioning why it might be controversial, or hell, what is controversial. What are the puzzling results? What constitutes being "near" the Solar System? What does this have to do with the existence/nonexistence of dark matter?

    • Agreed, atrocious summary and terrible title. Here's an alternate.

      Survey Finds Too Little Dark Matter Near Solar System

      The existence and approximate distribution of dark matter [wikipedia.org] have become standard assumptions in cosmology. According to Nature [nature.com], it "explains how structure arose in the Universe, how galaxies formed and how the rapidly spinning Milky Way manages to keep from flying apart." However, a paper [eso.org] recently accepted by the Astrophysical Journal studied stellar velocities in our part of the galaxy in an attempt to infer the amount of dark matter present near our solar system and came up with unsettling results. Moni Bidin, the study's lead author, concluded that "at most, only about one-tenth the amount of dark matter predicted by models could exist in the volume of space they examined." Astronomer Frederic Hessman, who is uninvolved in the study, put things bluntly [sciencemag.org]: "If this is right, it turns everything totally upside-down." Physicists are calling for caution and several note the difficulty and sensitivity to error of the present results. Astronomer Chris Flynn, who approved Bidin's paper for publication, cautioned, "I wouldn’t throw out nearby dark matter quite yet” and “The measurement being made is very challenging, and there are a number of ways for it to miss the dark matter even if is there.”

  • You would think that with a planet named Uranus there would be some somewhere. Oh did I really type that? My inner child is acting out again.
  • by 140Mandak262Jamuna (970587) on Friday April 20, 2012 @03:46PM (#39750337) Journal
    The dumb astronomers are looking in the outer space for it. No wonder they can't find it. All the dark matter in the solar system has coalesced into the form of Dick Cheney.
  • by OakDragon (885217) on Friday April 20, 2012 @03:54PM (#39750447) Journal
    ...they never asked me!
  • by Anonymous Coward

    The sun is RIGHT there. All they'd find is bright matter!

    But seriously folks. I'd advise you not be too attached to the idea that dark matter does or does not exist. The moment you aren't willing to accept evidence (which I won't say this survey is or is not given the possible flaws) and use said evidence to change your views, instead fighting to cling to your old beliefs (wassup geocentric epicycles), is the moment you stop being a good scientist.

    As always, I merely ask for more data.

  • by Jessified (1150003) on Friday April 20, 2012 @04:25PM (#39750781)

    Survey Finds No Hint of Dark Matter Near Solar System

    Survey:

    Earth: Anyone here composed of dark matter?
    Pluto: Not me!
    Saturn: Nay.
    Mars: Nope. ...

    • by PPH (736903)

      Pluto: Piss off! I'm not even a real planet according to you big shots. Right?

      [slams door]

  • I just thought that would be a better headline. Dark matter is actually the hypothesized solution to the missing mass problem. And it was supposed to be "right here"...

  • Aliens don't want us to see them, duh... They put up these shielded areas where they can do all sorts of strange stuff that we can't see.
  • by mbone (558574) on Friday April 20, 2012 @04:56PM (#39751107)

    It is disappointing that the original paper doesn't not appear to consider MOND (Modified Newtonian Dynamics) or TeVeS (a Tensor-Vector-Scalar theory of gravity, the relativistic version of MOND).

    The way to think about Dark Matter is it represents a problem with physics, namely excess force in the dynamics of galactic sized and larger objects. We don't know if the problem is with quantum field theories or with general relativity. The first possibility leads to theories such as Cold Dark Matter (CDM) or Weakly Interactive Massive Particles (WIMPs); the second to something like MOND / TeVeS. As literally pretty much all we know about Dark Matter is that there is excess force, neither approach can be ruled out at present.

    So, it's disappointing that they didn't consider the gravitational alternative. It's not clear from the paper whether or not MOND would survive this test. Unlike CDM or WIMP, MOND effects should be present at all places in the disk, so the real question is, are they compatible with these observations?

    • both those theories still need to be consistent with the bullet cluster
      • by mbone (558574)

        My understanding is that

        - there is no completely satisfactory theory of the Bullet Cluster and friends (such as A520 and DLSCL J0916.2+2951, although I am sure there will be a lot more to come) using any model, so I think it is premature to say they are conclusive and

        - The vector field in TeVeS may be able to explain the gravitational lensing of these clusters.

        What is less clear is whether this can be done without some dark matter or some field that acts like additional Dark Matter (on extra-galactic scales

    • It is disappointing that the original paper doesn't not appear to consider MOND (Modified Newtonian Dynamics) or TeVeS (a Tensor-Vector-Scalar theory of gravity, the relativistic version of MOND).

      From what I've read (e.g. this [scienceblogs.com], MOND can be parameterized to explain galactic rotation curves *better* than the dark matter hypothesis does. However, there are a variety of other reasons to believe there's something out there that might be loosely described as "dark matter", and for all those other reasons, MOND doesn't work at all.

      • by damburger (981828)

        Magic fairies pushing the stars around galaxies faster can be parametrized to explain rotation curves. You throw enough parameters at something, you are certain to get a solution.

    • by ceoyoyo (59147)

      MOND and relatives still require dark matter. The paper likely didn't consider them because their failure to keep up with cold dark matter in predictive power and simplicity really does put them in the long shot category, despite vehement defence by some people, most of whom seem to post on Slashdot.

  • Has anybody considered that it could be an alien race making planets (and therefore mass) invisible and just fucking with us?
  • Man, I was certain they'd detect Rush Limbaugh

  • It must be Quantum Dark Matter, it's only there when you're not looking for it. Attempts to observe it alter it.

  • No, it doesn't. Screw this, I'm done with shitty summaries and half-arsed ad-harvesting.

    • For that matter, "Neutrinogate" wasn't even a scandal. Yeah, it probably got more publicity than an unverified result merited, but the researchers did warn us that something could still be fishy, and that more work would be needed to see if something was wrong. They found a technical fault, fixed it, and are working on re-performing the tests. No big deal.

  • Historically, Dark Matter meant any matter not contained in a star emitting light. It originally did not mean exotic material of any kind per se.

    Now, the problem posed by Dark Matter is very real and valid. The issue is, as we get better at collecting accurate data about galaxies and better at detecting possible candidates, they all keep striking out. So, in order to match observed data, Dark Matter keeps picking up all of these exotic properties. On the one had this is progress, we are eliminating thin

  • by Livius (318358) on Friday April 20, 2012 @08:50PM (#39753039)

    People obsessing over whether dark matter is actually something like a material substance or really even a form of matter are missing the point. Dark matter is a hypothesis with explanatory power, and it very likely pointing to something that really exists. It may be many things acting together that are completely unrelated to the concepts of 'dark' and 'matter', or the current hypothesis might be a very natural explanation of what is causing the observed effects. The point is that there is a consistent theory which although not complete yet is helping us understand more about the universe.

    Consider things like quarks and elections, where we talk about waves and particles. But the notions of 'wave' and 'particle' are merely metaphors we use because the human imagination fails us in trying to describe things which according to the mathematics are clearly neither waves nor particles.

  • by Tom (822)

    Sometimes, not having english as your first language makes things funnier. The first meaning of the word "survey" that came to my mind this morning was 1 b) [merriam-webster.com] - "to query (someone) in order to collect data for the analysis of some aspect of a group or area" and I was wondering if they had sent questionaires to all the planets on one of the Voyagers. :-)
     

  • [quote]It seems these results don't shed as much light as we'd hoped.[/quote] It's not supposed to. It is dark matter

If the facts don't fit the theory, change the facts. -- Albert Einstein

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